Rivet set and method of making same



Patented Feb. 27,1923.

' srnnr. corarsn OF,BETHLEHLEl/i, rnnnsrrvnnra, a oo'nro-nnrronbr PENN;

SYLVANIA. V

' mew s n'r nun iunrnon or MAKING 1 a .Application filedijjlune is, 1921. SeriaLIl'o. 477,743.,

chines and is designed-to improvelthe structural character stlcsof the material' n an old and well known form of rivet "set; such as steel, giving it greater'strength, efiiciency and lasting qualities. One essential feature of it is that the longitudinally extending central core is hard while the surrounding integral exterior portion is tough and fatigue resisting from the contact end to a point beyond that where breakage in use usually occurs in such devices. The invention consists in the structurally novel product or article and the method of producing it. The novel features will be understood from the following description and claims taken with the drawing.

In the: drawing:

Figure 1 is a longitudinal section of a rivet set having an old and well known outward form, but showing small holes or connecting passageways drilled therein, and

Figure 2 isa cross section on the line 2-2 of'Fi re 1.

As is we 1 known in the art, the blow of the piston of the pneumatic riveter is liniited to a comparatively small central circular portion of the end-surface 10 of the shank or reduced cylindrical portion 11, and the tendency to break under the strains of use is greatest at the inner end of the shank or reduced cylindrical portion 11 at the point where it integrally joins the enlarged flange 12 of the body portion. It is necessary for efiicient use that the contact surface shall be hardyand to this end the common practice has been to subject the article to a treatment which hardens it throughout, but this has proved unsatisfactory because it makes the metal brittle and the upper shank or reduced cylindrical. portion 11 often breaks, thus not only destroying its usefulness but scorin and injuring the cylinder of the pneumatic i e er- The present in portionbeyond the flange 12.

in the central contact porti n whildiprov'idmg that l i i t n ecur all of the h rnes desired rounding a JOHN JAMES corner, or BETHLEHEM, rnnnsrrvnnm, assreno-nronnrnrnnnivt I hard core throughout. the shank which is hkely to-break' with" integral s ur d supporting metal} which is su'ffi'ci'ently tough and strong to sustainthe strains in use and'preventbreakage". To

this end a hole or passageway is drilled centrally in j the contact end 1'O; longitudinally of the rivet set through thej shanklor cylindrical portion 11 to the point I4Ein the enlarged cylindrical part -1 51of; the body S-dm wh smaller radlal holes or passageways 1" erably' four inj number lare ,then jdrilled'in the cyli dricet po n 115, equally spacefd around the circumference andflat them. in ncr' ends enteringthe lon itudinarfieestgtway 13 at its inner end. The article or tool 1s then heated to a temperature of approximately 1460 degrees F. and water is forced under pressure into the radial holes or passageways l6 and of course travels along passagcway Band is discharged at the contact end 10. Thls rapid passage of water through the interior of the tool from the inner end of hole 13 to its outer'end of course causes a rapid and uniform cooling from the center line outward and when the temperature of the outer walls of the tool has fallen to about 900 degrees F., further cooling by water is discontinued, and the tool is then plunged in oil and is allowed to cool further In a normal way. The result of this treatment or operation is to leave the central longitudinal core portion hard or of a mar-V tinsitic structure surrounded by .a sheath of material thickness composed of metal which structure extending out to the surface.

Having thus described my invention, what is claimed as new and desired to be secured by Letters Patent is: 7

1. A rivet set having a hard core of mattinsitic structure longitudinally of the shank extending to the end contact surface and an integral surrounding sheath or body of is tough and fatigue resisting or of sorbitic metal which is tough and fatigue resisting in character and of sorbitic structure.

2. A rivet set having a small central longitudinal hole or passageway in the shank from the contact end'surrounded by a hard metal core of martinsitic structure and an outer integral sheath of metal around the 7 core which is tough and fatigue resisting in character and sorbitic in structure.

3. As an article of manufacture, a rivet set for pneumatic riveters having radial holes. or passageways in its body portion entering the inner end of a central lOIlgl-,

tudinal passageway extending out through the shank to its contact end, ahard core oi "martinsitic structure surrounding said longitudinal passageway and an integral sheath or body of metal which is tough and fatigue resisting in character and sorbitic in structure surroundin said hard core.

I l. The method of treating a rivet set t give it desired characteristics which consists V in heating it to a high temperature, rapidly cooling its shank portion from its center line outward to such anjextent as to form ahard central core and then so cooling the entire body that the sheath of metal .sur-

rounding the hard central core will be tough and fatigue resisting. v

5. The method of treat1n arrlvet set for I u b I a 4 pneumatic riveters which consists in heating it to a temperature of approximately 1460 "degrees F., rapidly cooling its shank portion from its center line outward until the temperature of, the outer surface falls to about 900 degrees F., then dipping it in oil and allowing it to cool to normal temperature.

6. The method of treating a metal rivet set to give it desired characteristics which 'consists in heating it to a high temperature and then passing a stream ofwater under pressure through a small central passageway extending from within the body portion to the contact end of the shank until the central core portion of the metal extending only part way to thesurface has. become hard and of martinsitlc structure-and then ceasing the water cooling and plunging'hthe' article in oil and allowing it to cool.

7. The method of treating a metal rivet set to give it desired characteristics which consists in heating it to a temperature oi approximately 1460 degrees F, forcing water under pressure through laterally extend:

ing passageways in the body portion and a connected central passageway 'out through the contactend of the shank until the temperature of the outer surface falls to about 900 degrees F, and then plungingit in oil. In testimony whereof I hereunto. ai lix my signature; 1

JOHN JAMES corner. 

